Slack-adjuster.



H. ROSE.

SLACK ADJUSTER.

APPLICATION FILED, JUNE 6, 1914.

1,144,866., Patented Julie 29, 1915.

3 SHEETS-SHEET l.

WITNESS ES INVE/V TOR M ATroAwfrs THE NORRIS PETERS ca, PHOTQLITHQ,WASHINGTON, D. c.

'H. ROSE.

SLACK ADJUSTER.

APPLICATION FILED JUNE 6, 1914.

Patented June 29, 1915.

3 SHEETS-SHEET 2.

k y W P M a i 5 m w W 7 A WI T/VES SE6 THE NORRIS PETERS 60.,PHmfO-LlTHQ, WASHINGTON. D l:

H. ROSE 'SLACK ADJUSTER. APPLICATION FILED JUNE 6,1914

1,144,866., Patented June 29, 1915.

3 SHEETSSHEET 3.

THE NORRIS PETERS C0.. FHDWLITHO WASHINGTGN. D. C.

HUGH ROSE, 0F STANIVIOIRE, NEW SOUTI-I'WALES, AUSTRALIA.

SLACK-ADJUSTER.

To all whom it may concern:

Be it known that I, HUGH Rose, a subject of the King of Great Britainand Ireland, and resident of Yonka, Holt street, Stanmore, in the Stateof New South Tales, Commonwealth of Australia, have invented certain newand useful Improvements in Slack-Adjusters; and I do hereby declare thatthe following is a full, clear, and exact description of the same.

The slack of brakes is the amount of play between the brake shoes andthe wheel tires when the former are hanging free, and it is obvious thatas the shoes wear away by friction the amount of slack increases and themovement of the pull-rod and links required to bring the shoes intocontact with the tires increases proportionately to the wear.

The object of this invention is toprovide a more simple and positiveyetequally efiicient slack adjuster involving the use of a ratchet wheelbut not employing screw gear. And according to this invention the saidratchet wheel is independent of the brake cylinder (thus rendering thedevice applicable also to hand brakes if desired) being mounted in thelink and lever system of the brake mechanism and engaged by a pawl andhaving within, upon, or connected to it an eccentrically disposed camsurface engaging an adjusting link connected to an element of the saidsystem, abnormal movement of the main operating lever causing the saidpawl to rotate the ratchet wheel and the cam surface, whereby theeffective length of the adjusting link is reduced and the slack taken upautomatically as required. I have found that in practice the saidcamsurface preferably consists of a slot eccentrically disposed orconstituting a substantially involute curve within the periphery of thewheel, and this construction is illustrated in the accompanying drawingsforming part of this specification, which also show practical means ofcarrying the invention into effect and to which I will now refer: H IFigure 1 is a perspective view showing the ratchet wheel, the adjustinglink, and their immediate attachments as adapted for clasp brakes, theparts being shown in the normal position, that is to say set to give thedesired or normal amount of slack. Fig. 2 is a side elevation of Fig. 1.Fig. 3 is a sectional plan through the ratchet wheel Specification ofLetters Patent.

and part of the adjusting link. Fig. 4C is a iagrammatic side elevationshowing more completely the lever system and the pullrod, the partsbeing shown in the positions they would occupy when the automaticadjustment has reached its limit and the brake system requires resettingor new shoes. Fig. 5 is a diagrammatic view showing an arrangement ofparts for the application of the invention to a double system of claspbrakes. Fig. 6 is a diagrammatic view showing the invention applied to aclasp brake engaging two separate wheels and the introduction of anadditional ratchet wheel having two slots. Fig. 7 is a diagrammatic viewshowing a simple application of the invention to single brakes, with theparts relatively in the same positions as in Fig. 3. Fig. 8 illustratesdiagrammatically an arrangement of the wheel device more closely to theair brake cylinder. Fig. 9 illustrates the arrangement as in Fig. 1, butshowing a duplex ratchet wheel and the adjusting link passing betweenthe members of same.

'Referring to Figs. 1 to a inclusive :The ratchet wheel 10 is pivotallymounted on pin 11 between the lower extremities of the limbs of the mainbrake lever 12 which at its upper end is pivoted at 13 to the pull-rod14: connected to the brake operating mechanism (not shown), and withinsaid wheel is the curved slot 15 forming a substantially involute curve.Brake blocks 16 and 17 are fitted respectively with brake shoes 18 and19. adapted to bear upon the tread of the wheel 20 and are suspended inthe usual manner by links 21. 21. from the vehicle underframe.

To the brake block 16 is pivotally connected the pull link 22 which atits other end is pivotally connected to main lever 12, a series of pinholes 23. 23. being provided for manual adjustment purposes, either ofsaid holes being adapted to engage the pivot pin 24-. And the brakeblock 17 is pivotally attached to link 25 which at its other end ispivotally connected to lever 26 pivoted at its upper end to the vehicleunderframe and at its lower end at 27 to the adjusting link 28. Thelatter extends horizontally to the ratchet wheel 10 being bifurcated topass on each side of same, and a pin 29 joining the extremities of thelimbs registers through the curved slot 15, while a slot 30 in each ofsaid limbs and through which registers the pin 11 permits longitudinalPatented June 29, 1915. Application filed June 6, 1914. Serial N 0.843,520.

' air brake cylinder 37 operating lever movement of the link 28relatively to said pin 11.

On the adjusting link 28 is affixed a collar 31 and a sliding stop-pawl32 adapted to engage the teeth of the wheel 10, being pressed into suchengagement by the coil spring 33 about said link. lever 12 is pivotedthe operating pawl 34: adapted to engage the teeth of the ratchet wheel10. I I

In Fig. 5 the same parts as have hereinbefore been described withreference to Figs. 1 to i inclusive, are shown, in addition to the thepiston rod 88 of which has a cross-head 39 to one end of which isattached the pull-rod 14 while to the other end is attached the rod 40which in applying the brakes is a push-rod, and for safety each ratchetwheel 10 is pivotally susaended on a link a1.

In Fig. 6 the construction is substantially a duplication of that shownin Fig. 5 except that the brakes clasp two separate wheels, and there isprovided an additional ratchet wheel 42 having two curved slots, pivotedon a'lever e3 the top of which is pivoted to the piston rod of the aircylinder 37, and from the said wheel 4:2 lead two adjusting links ateand as the latter'also constituting the pullrod of one brake system.lhis construction provides a multiplication of the automatic adjustmentmechanism, and furnishes greater scope for its operation.

In Fig. 7 the brcke block link 35 itself constitutes the adjusting link,and the ratchet wheel 10 is pivoted to the main lever 12 at a point 11in line with said link which is bifurcated and slotted to permitlongitudinal movement as before while the lower extremity of the mainlever is pivoted to a fixed strut 36 dependent from the vehicleunderframing.

In Fig. 8 the ratchet wheel 10 is arranged on the floating lever &6attached to the piston rod of brake cylinder 37, and the adjusting link28 is connected to the floating lever a7 pivoted rearwardly of the saidcylinder, and these two levers are connected respectively to pull-rodsas and 49.

In Fig. 9 it will be seen that the ratchet wheel is composed of twocheeks 10. 10. between which passes the adjusting link 28.

Assuming the brakes to be adjusted to have a normal amount of slack, andthe parts in the position shown in Figs. 1, 2 and '3, repeatedapplication of the brakes will wear the shoes and increase the slack,this necessitating greater movement of the 12 to apply the brakes.Should this movement of lever 12 become sufficient to cause the pawl 34:to engage a succeeding tooth the return movement of the lever will causepartial rotation of the ratchet wheel, with the result that by thecocentricity of the slot 15 the pin 29 is moved ing the effective And tothe main.

' the pawl 3 L to engage farther away from the pin 11 therebyreduclength of the adjusting link 28 and consequently the distancebetween the brake shoes. The stop pawl 32 retains thewheel 10 in theposition now occupi d and on the succeeding applications of the brakesthe same operation is repeated if the movement of lever 12 is sufficientto cause another tooth. Should the movement not be sufficient no furtherrotation of wheel 10 occurs until further wear of the shoes involvesabnormal movement of the lever 12. .The adjustment will be automaticallyrepeated until the parts assume the positions shown by dotted lines inFig. 2 and in full lines in Fig. 4:-

The operation in regard to Figs. 5, 6 and 7 will be readily understoodfrom the foregoing.

What I claim and desire to secure by Letters Patent is e i 1. In a brakelever system, a brake lever, a ratchet wheel-journaled in one end of thebrake lever, and provided with a cam slot, a pawl carried by the leverand engaging the ratchet wheel to rotate the same, an adjusting linkhaving a pin at one end engaging said cam slot, and a longitudinal slotin said adjusting link adjacent said end, through which the journal pinof the ratchet wheel extends, and a stop pawl mounted to slide on theadjusting link and engaging said ratchet wheel.

2. In a slack adjuster for brakes the combination with the brake blocks,of a ratchet wheel having an eccentrically curved slot, an adjustinglink having a pin at one'end engaging said slot, a brake lever in whichsaid ratchet wheel is mounted to turn, a pawl carried by said lever andengaging the ratchet wheel to rotate the same, the said adjusting linkhaving a longitudinal slot through which the journal pin of the ratchetwheel extends, a second lever pivotally connected with the other end ofsaid adjusting link, link connections between the said levers and thebrake shoes, a stop pawl mounted to slide on the adjusting link andadapted to engage the teeth of the ratchet wheel, and a spring held onsaid adjusting link and bearing on the said stop pawl; o

3. In an automatic slack adjuster for brakes, the combination with thebrakes, and operating associated with the brakes, ratchet wheelsjournaled in the levers, and provided with cam slots,each adjusting linkbeing provided with a longitudinal slot adjacent one end through whichthe, journal pin of a ratchet wheel extends, the adjusting link havingat said end a pin engaging the cam slot of said ratchet wheel, the saidratchet wheels acting on the adjusting links to ad'- just thesamewhereby the slack on'the brake shoes is taken up, pawls carried bythe oplevers therefor, of adjusting links crating levers for actuatingthe ratchet Wheels automatically as the brake shoes wear, and springpressed stop pawls mounted to slide on the adjusting links and engagingthe ratchet wheels.

4. An automatic slack adjuster for brakes, comprising a brake lever, aratchet wheel journaled in one end of the brake'lever and provided witha cam slot, a pawl carried by the lever and engaging the ratchet wheelto rotate the same, an adjusting link having a longitudinal slotadjacent one end through which the journal pin of the ratchet wheelextends, the said adjusting link being provided at said end with a pinengaging the said cam slot, a collar on the adjusting link, a stop pawlmounted to slide on the adjusting link, and a coil spring on saidadjusting link and bearing against the collar and the said stop pawl.

5. In an automatic slack adjuster for brakes, a brake lever, a ratchetwheel journaled between the lower ends of the members of the brake leverand provided with a cam slot, an operating pawl pivoted to the operatinglever and engaging the teeth of said ratchet wheel at one side thereofto rotate the ratchet wheel, a bifurcated adjusting link, the members ofwhich extend on each side of the ratchet Wheel, the adjusting linkhaving a longitudinal slot adjacent one end through which the journalpin of the ratchet wheel extends, the said adjusting link being providedat said end with a pin connecting the members of said link and engagingthe said cam slot, a stop pawl carried by the adjusting link andengaging the teeth of the ratchet wheel at the other end thereof,

and a spring coiled around the members of the adjusting link andpressing on the said stop pawl.

6. In an automatic slack adjuster for brakes, the combination with theoperating lever, and an adjusting link adjustably connected with saidlever, of a pawl bifurcated at one end, a pivot pin connecting themembers of the pawl with the operating lever, adjusting means connectedwith one end of the adjusting link and actuated by said pawl to adjustthe adjusting link, a link extending between the members of the pawl andadjustably mounted on the pivot of said pawl, and a brake blockconnected with said ink.

7 In an automatic slack adjuster for brakes, the combination with thebrake blocks, the operating lever, and an adjusting link adjustablyconnected at one end with the said lever, of a pawl bifurcated at itsupper end, a pivot pin connecting the members of thepawl with theoperating lever, adjusting means connected with one end of the adjustinglink and actuated by said pawl to adjust the adjusting link, a leverconnected with the other end of said adjusting link, a link connectedwith said last mentioned lever, and a' link extending between themembers of said pawl and mounted on the pivot pin of said pawl, the saidlinks being connected with the brake blocks.

Signed at Sydney, New South Wales, this 29th day of April A. D. 1914.

HUGH ROSE.

Witnesses:

WM. NEWTON, GHAs. HATTON.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. C.

